Review Question - QID 105562

Symptoms of dysarthria and ataxia in a teenage boy with the finding of pes cavus (high arches) seen in Figure A raises concern for Friedreich ataxia (FA). Cardiac dysfunction, such as congestive heart failure and arrhythmias, is a common cause of death in patients with FA.

FA is an inherited autosomal recessive disease characterized by progressive neurological dysfunction, including cerebellar ataxia, sensory loss, and weakness. While not fully understood, FA is thought to develop as a result of mitochondrial iron accumulation. Cardiomyopathy and arrhythmias are often present and can lead to death in middle age. Symptom onset most often occurs in early teenage years with most patients wheelchair-dependent by their mid-20s. Diagnosis is confirmed by identifying excessive numbers of GAA repeats in the Frataxin (FXN) gene. A family history of disease is often present, but is not required for diagnosis. In addition to cardiac complications, skeletal abnormalities such as kyphoscoliosis, pes equinovarus (club foot) and pes cavus (as in this patient) are characteristic exam findings.

Cook et. al review the clinical manifestations, diagnosis, and management of FA. They note characteristic exam findings that prompt suspicion of the diagnosis, such as pes cavus, kyphoscholiosis and dysarthria. They discuss common causes of death in patients with FA, the most common being congestive heart failure and other manifestations of cardiac dysfunction.

Figure A shows a high-arched foot, referred to as pes cavus, a physical exam finding present in up to 75% of patients with FA.

Video V shows an example of gait in FA.

Incorrect Answers:
Answer 1: Some patients with FA will develop associated type II diabetes mellitus. However, complications from diabetes are a less common cause of death in patients with FA

Answer 3: Lymphoma is common in patients with ataxia telangiectasia, an immunodeficiency syndrome with a presentation similar to that of FA (e.g. ataxia). However, it often presents at a younger age, and patients often have a history of recurrent infections. This patient's age and history is more suggestive of FA.

Answer 4: Renal failure is not a common cause of death in patients with FA. While congestive heart failure may result in secondary renal dysfunction (e.g. cardiorenal syndrome), congestive heart failure is the primary cause of death in most patients with FA.

Answer 5: Respiratory failure is common in patients with neuromuscular disorders such as myasthenia gravis. While some patients with FA may develop respiratory failure due to bulbar dysfunction, it is a less common cause of death.

Bullet Summary
Friedreich ataxia presents in teenage individuals with ataxia, kyphoscoliosis, pes cavus, and dysarthria, with death most commonly due to congestive heart failure.